Speaking from experience, I've used Don Best Premium (and still do), G&J Update, FeistLines, OddsWiz and Rx Live Lines. DBS Premium is by far and away the fastest and most complete lines program there is, but it comes at a premium price of $550.00 per month. G&J is still in its infancy stage, but has promise as they have attracted some of the bigger (sharper) books lately (Pinnacle, Bet Horizon, SirBet, etc.) although the program is very buggy. FeistLines is flat out horrible, as the lines are severly delayed when comparing the same sportsbook vs. DBS premium or the sportsbook web page. OddsWiz looks all but abandon now. Rx Live Lines is great, because there are people out there who want to make the program better, plus they are doing it for no charge. You won't be able to beat an online sportsbook with a line move, as they are delayed 30 - 45 seconds, but you still may be able to pop your local book. That being said, the 30-45 second delay is still BETTER than the Don Best Express lines, which costs I believe $150.00 per month.
Hope this helps.
CE